326 ENTOMOLOGY 



or about $50 for each farm. "A recent estimate by experts put the 

 yearly loss from forest insect depredations at not less than $100,000,000. 

 The common schools of the country cost in 1902 the sum of $235,000,000, 

 and all higher institutions of learning cost less than $50,000,000, making 

 the total cost of education in the United States considerably less than 

 the farmers lost from insect ravages. Thus it would be within the 

 statistical truth to make a still more startling statement than Webster's, 

 and say that it costs American farmers more to feed their insect foes 

 than it does to maintain the whole system of education for everybody's 

 children. 



" Furthermore, the yearly losses from insect ravages aggregate nearly 

 twice as much as it costs to maintain our army and navy; more than 

 twice the loss by fire; twice the capital invested in manufacturing agri- 

 cultural implements; and nearly three times the estimated value of the 

 products of all the fruit orchards, vineyards, and small fruit farms in the 

 country." (Slingerland.) 



Though most of the parasites of domestic animals are merely annoy- 

 ances, some inflict serious or even fatal injury, as has been said. The 

 gad flies persecute horses and cattle; the maggots of a bot fly grow in 

 the frontal sinuses of sheep, causing vertigo and often death; another 

 bot fly develops in the stomach of the horse, enfeebling the animal. 

 The worst of the bot flies, however, is Hypoderma lineata, the ox-warble, 

 which not only impairs the beef but damages the hide by its perforations ; 

 the loss from this insect for one period of six months (Chicago, 1889) was 

 conservatively estimated as $3,336,565, of which '$667,513 represented 

 the injury to hides. 



All sorts of foodstuffs are attacked by insects, particularly cereals; 

 clothing, especially of wool, fur or feathers ; also furniture and hundreds 

 of other useful articles. 



As carriers of disease germs, insects are of vital importance to man, 

 as we have shown. 



Beneficial Insects. The vast benefits derived from insects are too 

 often overlooked, for the reason that they are often so unobvious as 

 compared with the injuries done by other species. Insects are useful 

 as checks upon noxious insects and plants, as pollenizers of flowers, as 

 scavengers, as sources of human clothing, food, etc., and as food for 

 birds and fishes. 



Almost every insect is subject to the attacks of other insects, pre- 

 daceous or parasitic to say nothing of its many other enemies and but 

 for this a single species of insect might soon overrun the earth. There 

 are only too many illustrations of the tremendous spread of an insect 



